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1.
Mol Cell Biol ; 40(22)2020 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-32868290

RESUMO

Activating mutations in KEAP1-NRF2 are frequently found in tumors of the lung, esophagus, and liver, where they are associated with aggressive growth, resistance to cancer therapies, and low overall survival. Despite the fact that NRF2 is a validated driver of tumorigenesis and chemotherapeutic resistance, there are currently no approved drugs which can inhibit its activity. Therefore, there is an urgent clinical need to identify NRF2-selective cancer therapies. To this end, we developed a novel synthetic lethal assay, based on fluorescently labeled isogenic wild-type and Keap1 knockout cell lines, in order to screen for compounds which selectively kill cells in an NRF2-dependent manner. Through this approach, we identified three compounds based on the geldanamycin scaffold which display synthetic lethality with NRF2. Mechanistically, we show that products of NRF2 target genes metabolize the quinone-containing geldanamycin compounds into more potent HSP90 inhibitors, which enhances their cytotoxicity while simultaneously restricting the synthetic lethal effect to cells with aberrant NRF2 activity. As all three of the geldanamycin-derived compounds have been used in clinical trials, they represent ideal candidates for drug repositioning to target the currently untreatable NRF2 activity in cancer.


Assuntos
Antineoplásicos/farmacologia , Benzoquinonas/farmacologia , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Lactamas Macrocíclicas/farmacologia , Fator 2 Relacionado a NF-E2/antagonistas & inibidores , Fator 2 Relacionado a NF-E2/metabolismo , Animais , Antineoplásicos/química , Benzoquinonas/química , Benzoquinonas/metabolismo , Morte Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Feminino , Humanos , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Lactamas Macrocíclicas/química , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Transplante de Neoplasias , Neoplasias/tratamento farmacológico , Neoplasias/genética , Proteína Oncogênica v-akt/antagonistas & inibidores , Oxirredução , Paclitaxel/farmacologia
2.
Postepy Biochem ; 66(2): 91-99, 2020 06 27.
Artigo em Polonês | MEDLINE | ID: mdl-32700506

RESUMO

Cytochromes bc1 and c b6f are part of respiratory or photosynthetic machinery. The main role of these enzymes is to build proton motive force across the bioenergetic membranes by coupling the proton translocations with electron transfer from the pool of membrane-soluble quinones to water-soluble redox proteins. Despite many years of research, the mechanism of quinol oxidation is not fully understood. It is assumed that unstable form of a partially oxidized quinol ­ semiquinone is an intermediate state of this process and that it is also a potential electron donor in the side reaction of superoxide generation. This semiquinone has remained experimentally elusive over years but recently a semiquinone interacting with the reduced iron-sulfur cluster was identified as a new state of the enzyme. The results indicate that semiquinone coupled to the iron-sulfur cluster is most probably an additional state that can prevent side reactions, including superoxide generation.


Assuntos
Benzoquinonas/química , Benzoquinonas/metabolismo , Elétrons , Citocromos/metabolismo , Transporte de Elétrons , Oxirredução , Superóxidos/metabolismo
3.
AAPS PharmSciTech ; 21(5): 137, 2020 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-32419124

RESUMO

In the global incidence of peptic ulcer, with the associated rates of hospitalizations and mortality are increasing, in the United States, peptic ulcer disease affects approximately 4.6 million people annually, with an estimated 10% of the US population having evidence of a duodenal ulcer. The present research aims to find a novel treatment for ethanol induced ulcer by loading thymoquinone (TQ) on a nanostructured lipid carrier (NLC), using Compritol® 888 and coconut oil. The TQ-loaded coconut oil NLC was formulated using melt emulsification combined with a sonication method using Poloxamer 188 as a surfactant. Finally, the optimization of the formulations was performed on a three-factor, three-level Box-Behnken statistical design, with 85.63% entrapment efficiency of TQ in the optimized formulation. A biphasic release pattern of the formulation was recorded in an in vitro drug release study, where the initial burst release of the drug was observed in the first 2 h, followed by a gradual release. Later, the TQ-loaded coconut oil NLC was found to protect the gastric mucous membrane more effectively (78.95% in.; p < 0.01) in an alcohol-induced ulcer model, whereas the TQ suspension showed 30.87% inhibition (p < 0.05) of the ulcerative index, when compared with the ulcer control group. The histopathological evaluations of the stomach in ulcer-induced animals demonstrated protection potential of TQ-loaded coconut oil NLC against an alcohol-induced gastric ulcer. In a nutshell, the entrapment of TQ within the NLC was found to deliver the entrapped drug more effectively when administered through an oral route to possess a gastroprotective effect.


Assuntos
Benzoquinonas/administração & dosagem , Óleo de Coco/química , Etanol , Lipídeos/química , Nanoestruturas/química , Úlcera Gástrica/induzido quimicamente , Úlcera Gástrica/tratamento farmacológico , Animais , Benzoquinonas/química , Portadores de Fármacos , Emulsões , Ácidos Graxos , Masculino , Tamanho da Partícula , Poloxâmero , Ratos , Ratos Sprague-Dawley , Sonicação , Tensoativos
4.
Chem Biol Interact ; 320: 109022, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32112862

RESUMO

Epithelial mesenchymal transformation plays a crucial role in the metastasis of bladder cancer, which makes bladder cancer difficult to cure. Bladder cancer is the most common malignancy of the urinary system, and distant metastasis is the leading cause of death. Therefore, finding a bioactive drug that can specifically inhibit epithelial mesenchymal transformation may be a new direction for bladder cancer treatment in the future. Thymoquinone (TQ), the major active compound isolated from black seed oil (Nigella sativa), has been reported to exhibit anti-inflammatory and anticancer abilities. TQ can exhibit its antitumor effect by inhibiting the proliferation and metastasis of cancer cells. However, the underlying mechanism of TQ as a tumor inhibitor in bladder cancer remains poorly understood. First, in this research, we demonstrate that TQ can reverse EMT by upregulating epithelial markers, such as E-cadherin, and downregulating mesenchymal markers, such as N-cadherin and vimentin. Furthermore, we demonstrate that TQ can suppress the activation of the Wnt/ß-catenin signaling pathway and inhibit the expression of ß-catenin target genes, such as MYC, Axin-2, MMP7, CyclinD1 and MET, which play crucial roles in EMT and cancer progression. Additionally, we demonstrate that TQ can inhibit the growth of xenografts and restrict the formation of tumor metastatic foci in the lung. Taken together, our findings confirm the antimetastatic effect of TQ in bladder cancer cells for the first time and also provide new evidence for the development of TQ as a novel treatment for metastatic bladder cancer.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Benzoquinonas/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Benzoquinonas/química , Linhagem Celular Tumoral , Ensaios de Migração Celular , Movimento Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Estrutura Molecular , Proteínas Wnt/genética , beta Catenina/genética
5.
Food Chem ; 317: 126454, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32113140

RESUMO

The reaction efficiency of o-benzoquinones with amines (L-lysine, Nα-acetyl-L-lysine, glycine, L-methionine and L-arginine), thiols (L-cysteine and Nα-acetyl-L-cysteine) and protein (bovine serum albumin) were determined at pH 5.0, 7.0 and 8.0 and scan rate of 10, 50 and 100 mV/s by cyclic voltammetry. Nucleophiles containing multiple nucleophilic groups and nucleophilic group possessing low pKa value would enhance the reactivity of nucleophiles towards o-benzoquinones. The reactivity of different o-benzoquinones with L-lysine/L-cysteine followed the order: protocatechuic acid quinone ≈ catechol quinone > 4-methylbenzoquinone ≈ caffeic acid quinone > rosmarinic acid quinone > chlorogenic acid quinone. The reactivity of quinones would be decreased by the steric hindrance of substituents on quinone ring, and it would also be weakened by enhancing electron cloud density of quinone ring. Adducts generated by the interaction of 4-methylbenzoquinone with amines and thiols were tentatively identified as amine-quinone adduct and thiol-phenol adduct respectively by UPLC-QTOF-MS/MS and cyclic voltammetry.


Assuntos
Aminoácidos/química , Benzoquinonas/química , Técnicas Eletroquímicas/métodos , Aminas/química , Catecóis/química , Cromatografia Líquida , Cisteína/química , Hidroxibenzoatos/química , Fenóis , Quinonas/química , Compostos de Sulfidrila/química , Espectrometria de Massas em Tandem
6.
Chem Commun (Camb) ; 56(20): 3065-3068, 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-32049076

RESUMO

Herein, a novel stacked hexagonal prism, Ag@Ni-MOF-1, was designed and developed as an integrated SERS platform not only for successfully catalyzing the in situ synthesis of DA-quinone under physiological pH, but also for establishing an approach for specific determination of Cys, an important species in the brain related to Alzheimer's disease (AD).


Assuntos
Benzoquinonas/síntese química , Materiais Biomiméticos/química , Dopamina/síntese química , Níquel/química , Compostos Organometálicos/química , Prata/química , Benzoquinonas/química , Catálise , Cisteína/análise , Dopamina/química , Humanos , Concentração de Íons de Hidrogênio , Compostos Organometálicos/síntese química , Análise Espectral Raman
7.
Biochemistry (Mosc) ; 85(2): 167-176, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32093593

RESUMO

Thymoquinone is one of the main active components of the essential oil from black cumin (Nigella sativa) seeds. Thymoquinone exhibits a wide range of pharmacological activities, including neuroprotective action demonstrated in the models of brain ischemia/reperfusion, Alzheimer's and Parkinson's diseases, and traumatic brain injury. The neuroprotective effect of thymoquinone is mediated via inhibition of lipid peroxidation, downregulation of proinflammatory cytokines, maintenance of mitochondrial membrane potential, and prevention of apoptosis through inhibition of caspases-3, -8, and -9. Thymoquinone-based mitochondria-targeted antioxidants are accumulated in the mitochondria and exhibit neuroprotective properties in nanomolar concentrations. Thymoquinone reduces the negative effects of acute and chronic forms of brain pathologies. The mechanisms of the pharmacological action of thymoquinone and its chemical derivatives require more comprehensive studying. In this paper, we formulated the prospects of application of thymoquinone and thymoquinone-based drugs in the therapy of neurodegenerative diseases.


Assuntos
Benzoquinonas/farmacologia , Doenças Neurodegenerativas/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Doença Aguda , Benzoquinonas/química , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Doença Crônica , Humanos , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Fármacos Neuroprotetores/química
8.
Org Biomol Chem ; 18(7): 1343-1348, 2020 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-32003394

RESUMO

Reported herein is a practical route to access synthetically challenging and chemoselective α,α'-diarylmethyl N-glycosides via Sc(OTf)3-catalyzed 1,6-conjugate addition of amino sugars with para-quinone methides (p-QMs). The reactions proceed smoothly without a base and under mild reaction conditions with a broad substrate scope and moderate to good yields.


Assuntos
Aminas/química , Benzoquinonas/química , Carboidratos/química , Glicosídeos/síntese química , Glicosídeos/química , Estrutura Molecular , Estereoisomerismo
9.
Acta Pharm ; 70(3): 325-342, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32074066

RESUMO

The aim of this study was to investigate the stability of three major antioxidants of Nigella sativa: thymoquinone (TQ), carvacrol (CR) and thymol (THY), under different stress conditions using HPLC and LC-MS/MS. Forced degradation for each compound was performed under different conditions, including oxidation, hydrolysis, photolysis and thermal decomposition. The results showed that both CR and THY were stable under the studied conditions, whereas TQ was not affected by acidic, basic and oxidative forced conditions but the effect of light and heat was significant. The degradation products of TQ were further investigated and characterized by LC-MS/MS. HPLC-UV method has been fully validated in terms of linearity and range, the limit of detection and quantitation, precision, selectivity, accuracy and robustness. The method was successfully applied to quantitative analysis of the principal antioxidants of Nigella sativa TQ, CR and THY in different phytopharmaceuticals.


Assuntos
Antioxidantes/análise , Benzoquinonas/análise , Cimenos/análise , Timol/análise , Antioxidantes/química , Antioxidantes/isolamento & purificação , Benzoquinonas/química , Benzoquinonas/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Cimenos/química , Cimenos/isolamento & purificação , Estabilidade de Medicamentos , Nigella sativa/química , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem , Timol/química , Timol/isolamento & purificação
10.
Food Chem ; 313: 126129, 2020 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31935665

RESUMO

Thymoquinone is a chief phytochemical constituent of black cumin seed oil (BCSO) and shows strong bioactivity. It has a weak stability against environmental conditions like heat and light. Encapsulation process by Saccharomyces cerevisiae is a popular technique to preserve the bioactivity and increase the stability of functional bioactive compounds. In the current study, BCSO was encapsulated by both plasmolysed (PYC) and nonplasmolysed yeast cell (NPYC) and stability of thymoquinone and bioactive properties of all samples were evaluated. And also, some physicochemical, morphological and conformational characterizations were carried out for the encapsules. The results showed that thymoquinone concentration and its bioactivity were preserved better in PYC during storage compared to BCSO and NPYC. The highest degradation ratio of thymoquinone during storage for the BCSO was 96.78% while the lowest one was for the PYC sample (52.63%).


Assuntos
Benzoquinonas/química , Cápsulas/química , Nigella sativa/metabolismo , Óleos Vegetais/química , Saccharomyces cerevisiae/química , Benzoquinonas/metabolismo , Depuradores de Radicais Livres/química , Nigella sativa/química , Sementes/química , Sementes/metabolismo
11.
J Enzyme Inhib Med Chem ; 35(1): 565-573, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31969031

RESUMO

Embelin is a naturally occurring para-benzoquinone isolated from Embelia ribes (Burm. f.) of the Myrsinaceae family. It was first discovered to have potent inhibitory activity (IC50 = 4.2 µM) against α-glucosidase in this study. Then, four series of novel embelin derivatives were designed, prepared and evaluated in α-glucosidase inhibition assays. The results show that most of the embelin derivatives synthesised are effective α-glucosidase inhibitors, with IC50 values at the micromolar level, especially 10d, 12d, and 15d, the IC50 values of which are 1.8, 3.3, and 3.6 µM, respectively. Structure-activity relationship (SAR) studies suggest that hydroxyl groups in the 2/5-position of para-benzoquinone are very important, and long-chain substituents in the 3-position are highly preferred. Moreover, the inhibition mechanism and kinetics studies reveal that all of 10d, 12d, 15d, and embelin are reversible and mixed-type inhibitors. Furthermore, docking experiments were carried out to study the interactions between 10d and 15d with α-glucosidase.


Assuntos
Benzoquinonas/farmacologia , Desenho de Fármacos , Inibidores de Glicosídeo Hidrolases/farmacologia , alfa-Glucosidases/metabolismo , Benzoquinonas/síntese química , Benzoquinonas/química , Relação Dose-Resposta a Droga , Embelia/química , Inibidores de Glicosídeo Hidrolases/síntese química , Inibidores de Glicosídeo Hidrolases/química , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Relação Estrutura-Atividade
12.
Biochim Biophys Acta Proteins Proteom ; 1868(2): 140335, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31785381

RESUMO

Pyranose oxidase (POx) catalyzes the oxidation of d-glucose to 2-ketoglucose with concurrent reduction of oxygen to H2O2. POx from Trametes ochracea (ToPOx) is known to react with alternative electron acceptors including 1,4-benzoquinone (1,4-BQ), 2,6-dichlorophenol indophenol (DCPIP), and the ferrocenium ion. In this study, enzyme variants with improved electron acceptor turnover and reduced oxygen turnover were characterized as potential anode biocatalysts. Pre-steady-state kinetics of the oxidative half-reaction of ToPOx variants T166R, Q448H, L545C, and L547R with these alternative electron acceptors were evaluated using stopped-flow spectrophotometry. Higher kinetic constants were observed as compared to the wild-type ToPOx for some of the variants. Subsequently, the variants were immobilized on glassy carbon electrodes. Cyclic voltammetry measurements were performed to measure the electrochemical responses of these variants with glucose as substrate in the presence of 1,4-BQ, DCPIP, or ferrocene methanol as redox mediators. High catalytic efficiencies (Imaxapp/KMapp) compared to the wild-type POx proved the potential of these variants for future bioelectrocatalytic applications, in biosensors or biofuel cells. Among the variants, L545C showed the most desirable properties as determined kinetically and electrochemically.


Assuntos
Desidrogenases de Carboidrato/metabolismo , Técnicas Eletroquímicas/métodos , 2,6-Dicloroindofenol/química , Benzoquinonas/química , Biocatálise , Desidrogenases de Carboidrato/química , Desidrogenases de Carboidrato/genética , Domínio Catalítico , Eletrodos , Compostos Ferrosos/química , Glucose/química , Glucose/metabolismo , Cinética , Metalocenos/química , Mutagênese Sítio-Dirigida , Oxirredução , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Trametes/enzimologia
13.
Exp Parasitol ; 209: 107810, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31801691

RESUMO

Fasciolosis is a neglected tropical disease caused by the liver fluke Fasciola gigantica. The absence of successful vaccine and emerging resistance in flukes against the drug of choice, triclabendazole, has necessitated the search for alternatives including phyto-therapeutic approaches. Curcumin and thymoquinone, the active ingredients of Curcuma longa and Nigella sativa plants respectively, were first screened for their binding affinity with Glutathione-S-transferase (GST) molecule through in silico molecular docking followed by in vitro treatment of worms with varying concentrations of the test compounds. The in silico molecular docking of curcumin and thymoquinone with sigma GST revealed strong hydrogen bonding as well as hydrophobic interactions with high fitness scores but showing inter-specific differences. The in vitro treatment of F. gigantica worms with both curcumin and thymoquinone resulted in a significant increase in the generation of reactive oxygen species (ROS) whereas the level of reduced glutathione, a primary redox regulator, was found to be significantly decreased (p < 0.05). The two compounds not only inhibited the GST activity, which is an important detoxification enzyme and also a key drug/vaccine target for the control of fasciolosis but also significantly inhibited the activity of antioxidant enzymes glutathione peroxidase and glutathione reductase that are vital in maintenance of redox homeostasis. The immunohistochemistry performed using anti sigma GST polyclonal antibodies revealed that both the compounds used in the present study significantly reduced immunofluorescence in the vitellaria, developing eggs present in the ovary and the intestinal caecae indicating inhibition of GST enzyme in these regions of the worms. Further, following treatment with curcumin and thymoquinone, chromatin condensation and DNA fragmentation was also observed in F. gigantica worms. In conclusion, both curcumin and thymoquinone generated oxidative stress in the worms by production of ROS and significantly inhibiting their antioxidant and detoxification ability. The oxidative stress along with induction of apoptotic like events would compromise the survival ability of worms within the host. However, further studies are required to establish their anthelmintic potential alone and in combination with the commonly used anthelmintic drugs under in vivo conditions.


Assuntos
Apoptose/efeitos dos fármacos , Benzoquinonas/farmacologia , Curcumina/farmacologia , Fasciola/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Animais , Benzoquinonas/química , Búfalos , Cromatina/efeitos dos fármacos , Curcumina/química , Dano ao DNA/efeitos dos fármacos , Fragmentação do DNA/efeitos dos fármacos , Eletroforese em Gel de Ágar , Inibidores Enzimáticos/farmacologia , Fasciola/citologia , Fasciola/metabolismo , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Glutationa Transferase/antagonistas & inibidores , Glutationa Transferase/química , Glutationa Transferase/metabolismo , Imuno-Histoquímica , Microscopia Confocal , Modelos Moleculares , Simulação de Acoplamento Molecular , Espécies Reativas de Oxigênio/metabolismo
14.
Int J Radiat Biol ; 96(2): 228-235, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31638880

RESUMO

Purpose: To evaluate the antioxidant and radio-protective effects of Nigella sativa oil (NSO) and thymoquinone (TQ) on radiation-induced oxidative stress in brain tissue.Materials and methods: Fifty-four Sprague-Dawley rats were divided into six groups to test the radio-protective effectiveness of Nigella sativa oil and thymoquine administered by either orogastric tube or intraperitoneal injection. Appropriate control groups were also studied.Results: Brain antioxidant capacity, as measured by the levels of total superoxide scavenger activity (TSSA), non-enzymatic superoxide scavenger activity (NSSA), superoxide dismutase, paraoxonase (PON) activities, total antioxidant status and total sulfhydryl (-SH) group, were lower in the irradiation (IR) only group while xanthine oxidase (XO) activity, total oxidant status (TOS), oxidative stress index (OSI) and lipid hydroperoxide (LOOH) levels were higher in the group compared with all other groups. Brain glutathione-S-transferase (GST) activity significantly decreased in the IR only group when compared with the control groups. Glutathione peroxidase (GSH-Px) activity was lower in the IR only, NSO plus IR, TQ plus IR groups when compared with the control group of TQ. Arylesterase (ARYL) activity was not statistically significant in the IR only group compared with all other groups.Conclusions: The results suggest that Nigella sativa oil (NSO) and its active component, TQ, clearly protect brain tissue from radiation-induced oxidative stress.


Assuntos
Benzoquinonas/farmacologia , Encéfalo/efeitos dos fármacos , Encéfalo/efeitos da radiação , Raios gama , Estresse Oxidativo , Óleos Vegetais/farmacologia , Animais , Antioxidantes/química , Benzoquinonas/química , Radicais Livres , Peroxidação de Lipídeos , Nigella sativa/química , Óleos Vegetais/química , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Superóxidos/química
15.
Food Chem ; 307: 125554, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31648176

RESUMO

The reaction of Nε-(carboxymethyl) lysine (CML) with eight kinds of non-flavonoid o-benzoquinones and five kinds of flavonoid o-benzoquinones were investigated by cyclic voltammetry at pH 5.0, 7.0 and 8.0 and scan rate of 10, 50 and 100 mV/s. The reactivity of o-benzoquinones towards CML is weakened by the electron-donating substituent and strengthened by the electron-withdrawing substituent on the o-benzoquinone rings. The steric hindrance of the substituents on o-benzoquinone rings also weakens the quinone reactivity. Reaction of 4-methylbenzoquinone with CML (38.0 ±â€¯1.3%) was found to be faster than that with l-lysine (31.3 ±â€¯1.5%) and Nα-acetyl-l-lysine (14.5 ±â€¯0.1%) but slower than that with l-cysteine (≥100.0%) and Nα-acetyl-l-cysteine (≥100.0%) at pH 7.0 and scan rate of 10 mV/s. Products obtained by the reaction of CML with o-benzoquinones were found to include a CML-quinone adduct according to the cyclic voltammetry and UPLC-QTOF-MS/MS analysis.


Assuntos
Benzoquinonas/química , Lisina/análogos & derivados , Catecóis , Cisteína/química , Flavonoides , Lisina/química
16.
J Agric Food Chem ; 68(1): 340-350, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31874034

RESUMO

Folic acid, a synthetic form of folate, is a water-soluble vitamin that is essential during periods of rapid cell division and growth. However, it decomposes upon ultraviolet irradiation to form inactive photoproducts. In this study, the protective effect and mechanisms of antioxidants, including cinnamic acids, flavonoids, catechol and its derivatives, stilbenes, p-benzoquinone and its derivatives, isoprenoids, curcumin, oleic acid, and linoleic acid, against folic acid photodecomposition were investigated by using fluorescence and absorbance spectroscopy, high-performance liquid chromatography, and antioxidant assay. It was found that antioxidants could inhibit or delay the folic acid decomposition in varying degrees, among which caffeic acid was the most effective. The increase in its remarkable antioxidant efficiency and absorbance in the UVA region during irradiation contributed to its effective protection. This finding could be useful for the protection of photolabile components in food and other uses.


Assuntos
Antioxidantes/química , Ácido Fólico/química , Benzoquinonas/química , Catecóis/química , Cinamatos/química , Flavonoides/química , Fotólise/efeitos dos fármacos , Fotólise/efeitos da radiação , Estilbenos/química , Raios Ultravioleta
17.
Food Chem ; 309: 125697, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31727513

RESUMO

Formation of green trihydroxy benzacridine (TBA) derivatives when chlorogenic acid (CGA) quinones and amino acids react can be unappealing for some consumers. Cysteine was studied as an anti-greening strategy, given that cysteine-CGA conjugates are colorless. Buffered 2.55 mM CGA: 5.09 mM lysine: (0-5.09) mM cysteine solutions at pH 8 and 9 were prepared and incubated for a maximum of 48 h at 22 C. Color intensity and conjugate formation was monitored spectrophotometrically, and by HPLC and LC-MS respectively, while antioxidant capacity was measured by Folin-Ciolcateau and Trolox equivalent antioxidant capacity assays. Green TBA formation was promoted at higher pH and inhibited as cysteine concentration increased. Concentration-dependent cysteine inhibition of CGA-lysine greening was attributed to redox diphenol regeneration and formation of cysteinyl-CGA conjugates, which also contributed to antioxidant capacity. pH had a greater effect on antioxidant capacity than added cysteine. Results suggested a potential anti-greening approach for alkaline CGA quinone-amine greening.


Assuntos
Antioxidantes/química , Benzoquinonas/química , Cisteína/química , Ácido Clorogênico/química , Cromatografia Líquida de Alta Pressão , Cor , Reação de Cicloadição , Concentração de Íons de Hidrogênio , Espectrometria de Massas , Oxirredução
18.
Chemosphere ; 239: 124722, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31494318

RESUMO

Perfluorooctanoic acid (PFOA) has attracted considerable attention worldwide due to its widespread occurrence and environmental impacts. This research focused on the photocatalytic process for the treatment of PFOA in water and wastewater. Gallium oxide (Ga2O3) and peroxymonosulfate (PMS) were mixed directly in PFOA solution, which was irradiated under different light sources. The treatment system showed excellent performance that 100% PFOA was degraded within 90 min and 60 min under 254 nm and 185 nm UV irradiation, respectively. Moreover, the degradation efficacy was unaffected by initial PFOA concentration from 50 ng L-1 to 50 mg L-1. Acidic solution (pH 3) improved the degradation process. The quantum yield in the PMS/Ga2O3 system under UV light (254 nm) was estimated to be 0.009 mol E-1. Scavengers such as tert-butanol (t-BuOH), disodium ethylenediaminetetraacetate (EDTA-Na2) and benzoquinone (BQ) were added into PFOA solution to prove that sulfate radicals (SO4•-), superoxide radical (O2•-) and photogenerated electrons (e-) were the main active species with strong redox ability for PFOA degradation in PMS/Ga2O3/UV system. Combined with the intermediates analysis, PFOA was degraded stepwise from long chain compound to shorter chain intermediates. In addition, PFOA in real wastewater exhibited similar degradation efficiency, together with 75-85% TOC removal by Ga2O3/PMS under 254 nm UV irradiation. Therefore, Ga2O3/PMS system was highly effective for PFOA photodegradation under UV irradiation, which has potential to be applied for the perfluoroalkyl substances (PFAS) treatment in water and wastewater.


Assuntos
Caprilatos/química , Fluorcarbonetos/química , Gálio/química , Peróxidos/química , Poluentes Químicos da Água/química , Benzoquinonas/química , Ácido Edético/química , Concentração de Íons de Hidrogênio , Oxirredução , Fotólise , Superóxidos/química , Raios Ultravioleta , Águas Residuárias/química , Água , Purificação da Água , Difração de Raios X
19.
Anal Chim Acta ; 1095: 197-203, 2020 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-31864622

RESUMO

Black phosphorus (BP) has a high charge-carrier mobility (∼1000 cm2 V-1 s-1), but the bare BP degrades rapidly in the presence of oxygen and water which limits the application of the BP. In this study, a simple, non-covalent passivation strategy is developed by modifying of the BP with hexamethylendiamine (HA). The functionalized BP exhibits good stability over 4 weeks. The organic phase interdigital electrode which is constructed by stable HA/BP and tyrosinase displays lowest noise signal (0.025 nA) and relatively low detection limit (10 nmol L-1) for bisphenol A. This work provides a new strategy for construction of novel biofuel cell, bioelectronics and biosensors.


Assuntos
Compostos Benzidrílicos/análise , Técnicas Biossensoriais/métodos , Disruptores Endócrinos/análise , Monofenol Mono-Oxigenase/química , Fenóis/análise , Fósforo/química , Compostos Benzidrílicos/química , Benzoquinonas/química , Diaminas/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Disruptores Endócrinos/química , Enzimas Imobilizadas/química , Limite de Detecção , Fenóis/química , Reprodutibilidade dos Testes
20.
Int J Pharm ; 575: 118920, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31863880

RESUMO

The hypothesis for the investigation was that the overall mechanism of action of skin penetration enhancers is best explained by the Solubility-Physicochemical-Thermodynamic (SPT) theory. To our knowledge, this is the first report of the application of SPT theory in transdermal/topical/enhancer research. The SPT theory puts forward the concept that the mode of action of enhancers is related to solubility parameters, physicochemical interactions and thermodynamic activity. This paper discusses these concepts by using experimentally derived permeation data, various physicochemical and solubility parameters (ingredient active gap (IAG), ingredient skin gap (ISG), solubility of active in the formulation (SolV) and the formulation solubility in the skin (SolS)) generated by using FFE (Formulating for Efficacy™ - ACT Solutions Corp) software. These studies suggest that there is an inverse relationship between measured flux and IAG values given that there is an optimum ingredient skin gap, SolV and SolS ratio. The study demonstrated that the flux is actually proportional to a gradient of thermodynamic activity rather than the concentration and maximum skin penetration and deposition can be achieved when the drug is at its highest thermodynamic activity.


Assuntos
Benzoquinonas/administração & dosagem , Excipientes/administração & dosagem , Nicotina/administração & dosagem , Absorção Cutânea , Administração Cutânea , Azepinas/administração & dosagem , Azepinas/química , Benzoquinonas/química , Eucaliptol/administração & dosagem , Eucaliptol/química , Excipientes/química , Humanos , Técnicas In Vitro , Modelos Teóricos , Nicotina/química , Ácido Oleico/administração & dosagem , Ácido Oleico/química , Polissorbatos/administração & dosagem , Polissorbatos/química , Propilenoglicol/administração & dosagem , Propilenoglicol/química , Pirrolidinonas/administração & dosagem , Pirrolidinonas/química , Pele/metabolismo , Software , Solubilidade , Termodinâmica
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